THE NINETEENTH ANNUAL MEETING. 89 



mal cells. These threadlike organs make up the body of the fungus, 

 forming what is known as the mycelium. 



"As soon as the fungus gets a good foothold, it prepares for its multipli- 

 cation and dissemination. For this purpose it develops a number of 

 upright shoots, or hijpluv, that correspond to the fruit-stalks of flowering 

 plants. If the fungus is one that lives within its host, these burst through 

 the epidermis or emerge through the stomata, and at their extremities the 

 spores are produced. The method of their production is very simple. 

 Either the hypluTe separate by means of cross-partitions, so that they 

 form a number of oval bodies resembling a string of beads, or they branch 

 and at their extremities the spherical or elliptical spores are produced. 

 These spores are minute bodies, varying in size from those that are barely 

 visible when magniiied with a microscope one hundred thousand times, to 

 others that can be made out when increased a few diameters. 



"The number of spores that can be produced by a fungus is almost 

 beyond computation. From a single spore, a plant body may develop 

 which in a few days will give rise to millions of spores, and each of these, 

 if given the right conditions, may repeat the operation, and so on for 

 weeks and months. They are light, and floating about in the air are often 

 wafted long distances by the wind. 



"While seeds of most of our higher ]>lants require a period of rest 

 before they can make a perfect development, the spores of fungi only 

 recjuire })roper conditions for immediate germination. If they fall upon a 

 moist surface they are ready for development, and with a proper tempera- 

 ture this takes place very rajjidly. If the spore falls on a plant that it can 

 use as a host, and finds there the proper conditions, it will push out one or 

 more mycelial threads, which will branch, and. according to their habit, 

 will spread through the tissues or remain on the surface and send their 

 haiistoria down to obtain nourishment. 



"In addition to the numeroiis generations of the conidia, or summer 

 spores, that have been described, most plants, toward the close of the 

 season, produce what are known as winter spores. These are usually oval 

 bodies, with a thick cell wall, and for protection a number of them are 

 l^acked away in what are known as spore cases. These in turn are 

 enclosed in a thick receptacle. The organs in which the winter spores are 

 dexeloped are genevally sporangia ov pen'fJiccid. The latter is the most 

 usual form. 



USE OF FUNGICIDES. 



"It may be well at this point to speak briefly concerning the use of 

 fungicides, in general, for the destruction of fungi. When a fungus has 

 once gained access to the interior of a plant, no fungicide can be applied 

 that will destroy it. If, on the other hand, the fungus is without the plant, 

 or the si)ores are attempting to gain entrance, we have at our disposal a 

 number of very efficient remedies. For a long time it has been known 

 that sulphur was a valuable fungicide, and various compounds of sulphur, 

 usually in the forms of sulphides and sulphates, are now used for this 

 purpose. Among the mixtures that are used for the destruction of fungi, 

 the following have proved valuable: 



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